In recent years, display devices to be used for advertisement have been developed, and these devices employ large screen displays. This display device allows using an animation for advertisement, so that the advertisement can draw more attentions. Reproduction of sound information such as voice, music, and effective sound allows drawing still more attentions to the advertisement. However, the sound information sometimes sounds noisily to passers-by.
To overcome this problem, a sound output control device, i.e. a sound reproducing device, has been proposed. This device employs an ultra-directional speaker (called as a parametric speaker) that gives a directivity to sound information, so that the sound information can be delivered only to a specific target. Japanese Patent Laid-Open Publication No. 2010-39094 discloses a conventional sound output control device, sound reproducing device. FIG. 5 is a perspective view of the conventional sound reproducing device.
Display device 101 that displays an advertise image includes display panel 103 implemented by a flat panel display, such as an LCD panel. Display device 101 is equipped with ultra-directional speaker 105 and camera 107 mounted to the upper end of device 101. Speaker 105 is supported by speaker pedestal 109 which includes a motor (not shown) so that an output direction of sound can be changed horizontally or vertically as indicated by the arrows shown in FIG. 5. Display device 101, ultra-directional speaker 105, camera 107, and speaker pedestal 109 are connected to a controller (not shown).
The above patent literature discloses that the controller detects persons captured by camera 107 as targets, and causes speaker pedestal 109 to adjust a direction of sound output from speaker 105 to be directed toward the targets, and then ultra-directional speaker 105 outputs the sound. As a result, the sound output from ultra-directional speaker 105 allows calling more attention to the advertisement from the persons within a range allowing the advertisement to be recognized.
The sound output control device shown in FIG. 5 allows ultra-directional speaker 105 to output a sharp directional sound to the targets captured by camera 107, so that only the specific targets can pay attention with the aid of the sound to the advertisement. As a result, the control device can reduce the possibility for the passers-by other than the targets to hear the sound noisily. On the other hand, since the sound has a sharp directivity, the sound may not delivered to passers-by other than the specified targets, so that the advertisement cannot fully draw attention from people.